FUNDAMENTALS OF COMPUTERS
Define COMPUTER? Explain the terms Hardware and Software?
Computer is an electronic device, which is used to input data, process the data under the user given instructions and gives the required output. Every computer contains three basic components. They are Input unit, Processing Unit and Output unit. Every computer works on the basic principal of I-P-O cycle.
Input Process Output
The computer technology is mainly divided into two parts.
HARDWARE is physical appearance of the computer. All the electrical and electronic components connected to the computer are called hardware.
Ex: Input devices, Output devices, Hard Disk, C.P.U etc
SOFTWARE is a set of programs written in a sequential order to do a particular work. A Program is a set of instructions written by user. Software is divided into two types.
1. System Software
2. Application Software
System Software: Software written to perform system –oriented functions is called system software.
Ex: Operating systems, Compilers, Interpreters, Assembles, etc
The main function of an Operating System is to activate the computer and allows the user to work with the computer. Operating system is the basic command interpreter which translates the user given instructions in to machine language and vice versa.
Interpreters are also translators and these cabs translate the instruction of high level language into machine language. But interpreters translate only one instruction at a time.
Compilers are used translate the User’s high-level language program into machine level language. They translate the entire source program to object code at a time.
Assemblers also translate the assembly language program into machine level language.
Application Software: Application software is the programs written to perform a particular task. These are useful in working with a particular work, and their functions are limited. There are so many types of application packages, Database Management Packages, Entertainment Software, Utility Software etc.
Explain the Characteristics of computer (or) advantages of computers (or) features of computers?
There are many advantages of computers.
Speed: Computers works at very high speed, they can add & subtract numbers, compare letters, move and copy with very high speed. The speed of computer is generally measured in terms of MIPS (Million Instructions Per Second).
Storage: Computers are capable of storing large amount of data in its memory. They can store million of characters of data in a condensed form. The data stored in computers can be measured in terms of “Bits” and “Bytes”.
Accuracy: Computers are very accurate. Computers do not do mistakes. They can perform thousand of operations with great accuracy as their circuits have no Mechanical part to wear and mal function. The Maximum computer mistakes are manual.
Diligence: Computers do not get bore, they can work for a long time with the same speed, when the system was started.
Versatility: Now a days, computers are widely using in different organization, the usage of computers in all fields like Education, Training, Business, Industries, Science and Engineering were increasing day by day.
LIMITATIONS OF COMPUTERS:
The computers have some disadvantages also.
They are not flexible as human beings.
It cannot think properly like human beings.
It won’t works without having the programs in it.
A computer must have little step described to it.
It a situation develops that is outside the scope of what has been described to it, erroneous results may be generated.
They are costly and are not easily accessible by common man in developing .
If more number of external devices is attached to the system, the speed of the system becomes less and less.
GENERATIONS OF COMPUTERS:
Evolution of modern computer from the olden days is known as Generations of Computers. Generation are divided has is on the following characters.
Increasing in Storage capacity
Increasing in Processing Speed
Increasing in Reliability
First Generation: [1948 to1959]: Vacuum Tubes are used a Main components in C.P.U. The digital computers using Vacuum tubes are electronic valves, known as first generation Computers. 3000 to 4000 Vacuum tubes are used for data transformation. So that, they occupies much space i.e., the systems are very big in size and high in cost, they consumed much electricity and generated considerable amount of heat. The first generation computers used Assembly language for programming. The system part works, vacuum tubes is burnt out until it replace by a new vacuum tube. They used Ferrite cores for main memory and Magnetic tapes for external storage punched cards are used for feeding information. Punched cards are used for getting results.
Second Generation: [1949 to1965]: The Second Generation used Transistors as main component in C.P.U. Transistor are invented William Shockley in 1948 with the usage of transistors there computers are much faster and reliable than generation computers. They used high level like FORTRAN is a language (1956). COBOL (1960), ALGOL (1960) and BASIC for programming. They used ferrite cores for main memory and Magnetic disc drums and Magnetic tapes for External Storage.
Third Generation: [1956 to1974]: In third generation Integrated Circuits [IC] were used as Main component in C.P.U. Integrated Circuits contains equivalent of many transistors. They used Magnetic core memory for main memory for main memory and also Semi conductor memories like RAM, ROM, Magnetic disc, Drums and Magnetic tapes was used as secondary memories. Multiprocessing, Multi used system where introduced in this generation. More high level languages like PASCAL were introduced in this generation.
Fourth Generation: [1971 to words]: In forth generation LSIC[Large Scale Integrated Chip] were used as Main component in C.P.U. These are also called Micro Processor A C.P.U. consists of one or more Micro processors. Each Micro processor contains more than one million transistors in it. The main improvements have been made in Speed, Memory, Size and Backing density of IC’s.
Fifth Generation: The fifth generation computers are under development stage. These computers use ULSI [Ultra Large Scale Integration] which contains millions of components into a single IC. This technology is called Expert system or Artificial Intelligence i.e., the computers than can think. The input and output information for these computers will be in the form of speech and graphic images. The computers will understand natural languages like English. The programmers will not have to learn programming languages. In Artificial intelligence the user will tell the computer what to do. The user will not tell the computer how to do.
CLASSIFICATION OF COMPUTERS ACCORDING TO PROCESSING:
There are three types of computers according to the logic on which they process the data.
Analog Computers: Analog computers recognize data as a computers physical property. The output is usually in the form of reading on dials or graphs. Voltage, pressure, speed and temperature are some physical properties that can be measured in Analog form. In analog computers, the data will be transmitted in the form of analog signals i.e., continuation flow of data and the result will be changed into the standard and measurement of physical properties.
Digital Computers: Digital computers recognized data by counting discrete signals representing either a high or low voltage state of electricity. Numbers, Alphabets & Special symbols can all be reduced to represent by one’s(1’s) and zero’s(0’s). The digital computer understand information composed of binary digits i.e., 0’s and 1’s. Binary digit is called Bit. A group of 8 Bits is called one BYTE. The components, which convert Alpha numeric characters to Binary format and binary output to alphanumeric characters, are the essential parts of a digital computer. Digital Computers are further grouped into two categories.
General Purpose Digital Computers: The digital Computers which can theoretically be used for any type of application are called general purpose digital computers for Ex. The computers that are used for payroll graphs, analysis, Account, Banking system etc.,
Special Purpose Digital Computers: these computers which are made and used for a particular task. For Ex. The computers installed in Automobiles to control Fuel Emission instrument & Breaking system.
Hybrid Computers: These are the combination of Analog and Digital computes. These computers will do the work of both analog and digital computers. They can take the date in Analog quantity and gives the output in Digital quantity in the same way takes the digital quantity as input and converts as Analog quantity.
Classification of computers according to Size, Cost and Processing Speed (Performance)
Types of Digital computers:
Modern computers are classified into the following types based on the size, cost and processing speed.
Micro computers: These are the smallest computers and low in cost and process the data with less processing speed. The memory capacity of this computer is very less. These computers are also called as Personal Computers (PC). The word length of micro computers will be in the range of 8 to 32 bit.
Mini computers: These are faster and powerful than micro computers. These systems are widely used as Servers in LAN (Local Area Network). In LAN these mini computers works as servers which shares the information, memory and proceeding speed to the connected computers. In LAN micro computers are used as Clients (or) nodes which gains the information and processing speed from the server (Mini computer). These mini computers are multi-user systems.
Mainframe computers: These computers are powerful than Mini computers. Mainframes process the data at several Million instructions per second. More than one thousand remote workstations can be accommodated by a typical Mainframe computer. These computers are used in large organizations where the people need frequent access to the same data. These computers are widely used in MAN (Metropolitan Area Network). In this network a technique that allows many people at different terminals to access the same computers at one time i.e. time sharing.
Super Computers: These are the fastest, most powerful and expensive computers in the world. Super computers recognizes the largest word length of 64 bits, 128bits or even higher. They can calculate at a speed of 7 Billion Instructions per Second. They can take input from over 10000 individual workstations. These computers are widely used in WAN (Wide Area Network). These are very useful in weather Forecasting, Weapon designing, Air craft designing, etc.
One of the most powerful Super computer is CRAY-II (USA). India’s Super computer was designed by CDAC and the name of the computer is PARAM.
COMPONENTS OF A DIGITAL COMPUTER
Block-Diagram of a COMPUTER
Every computer works on the basis principle of I-P-O Cycle.
Every computer contains the following common parts:
Microprocessor or CPU
Secondary storage devices
1. Input Unit: Input unit is used to give the data to the computer. Computer receives the data from the input unit. There are different types of input devices available in the market. The basic input device for every computer is Keyboard. Some other input devices are Mouse, Trackball, Joystick, Scanner, Barcode Readers, etc.
2. Output Unit: Output unit is used to present the processed result to the user. The basic output device is Monitor or VDU (Visual Display Unit). Some other output devices are Printers, Plotters and Speakers, etc.
3. Microprocessor (or) Central Processing Unit (CPU): Microprocessor is the hart of the computer, which is used to convert the user given data into meaningful information. Converting data into meaningful information is called Processing. Micro processor is collection of millions of transistors. Transistors are used to process the data in binary from. Some computers may contain one or more microprocessors inside the system unit. The microprocessor has 2 main units.
CU Stands for control unit. It controls the entire operations of computer. It is main part of the CPU. This controls all the system components by sending digital signals and also generates timing and execution of instruction or program.
The function of ALU is performing Arithmetic & Logic operation such as addition. Subtraction, multiplication, division, (Arithmetic Operation) and, or, not, exclusive or (logical operation).
4. Memory: - Memory is used to store the information. Every computer must contain some memory to store data. The memory required for every computer is called Main Memory or Internal Memory or Primary Memory. This primary Memory is divided into two types:
1. RAM (Random Access Memory)
2. ROM (Read Only Memory)
RAM is temporary memory and ROM is permanent memory. These two are compulsory required to run a computer.
5. Secondary Storage (or) External Storage: To store the information permanently we are using secondary storage devices. There are different types of secondary storage devices are available.
1. Magnetic Storage
2. Optical Storage
3. Magneto optical Storage.
CLASSIFICATION OF MEMORY:
Memory is used to store the information, data, Programs. Every computer must contain some memory to store data. There are two types of memories are available.
Primary / Main Memory is Compulsory required to run the computer.
Secondary Memory is used to store the data, information & programs permanently.
Main Memory (Or) Primary Memory:
This Primary memory is divided into two types.
1. RAM (Random Access Memory)
2. ROM (Read Only Memory)
RAM: This most common type of memory is RAM (Random Access Memory). This is the fastest memory in the computer. All the user given information will be directly addressed to computers Internal Memory i.e. RAM. All the contents of this memory will be accessed to the user. RAM is volatile memory i.e., it stores the information as long as power supply is on. If the power supply goes off, all the contents of RAM will be erased. This is a temporary memory. It stores input data, intermediate results and output results. There are different types of RAM’s available. These are some what advanced than RAM. They are SRAM (Static RAM) and DRAM (Dynamic RAM).
Static RAM: Static RAM retains stored information as long as the power supply is on.
Dynamic RAM: Dynamic RAM loses its information in very short time even the power supply is on.
ROM: Another Memory ROM (Read Only Memory) is also compulsory required to start up the computer. But it is a permanent memory i.e. the contents of this memory will not lost. This memory is already programmed by the Designers at the time of manufacturing the chip. This memory contains a program called BIOS (Basic Input Output System), which is useful in starting up the computer. The contents of this memory are not accessible to users. There are different types of advanced ROM’s available in the market. They are:
PROM: Stands for Programmable Read Only Memory. By using this Programmable ROM the users are capable to program once in the life span of that chip.
EPROM: Stands for Erasable Programmable Read Only Memory. This type of ROM allows the user to erase the contents inside the chip and to store new programs. Focusing this chip to high intensity of Ultra Violet Rays will erase the data inside it. This technique is very hard because every time if the user wants to delete and reprogram, the user have to remove the ROM chip from the CPU and have to put it before UV Rays. This is very risky process.
EEPROM: Stands for Electrically Erasable Programmable Read Only Memory. This type of Chip is very easy to program any number of times. The contents of this chip will be erased with a single command. We can erase any part of the program inside the chip. It works with a single electric flash, which will be focused on the chip and deletes the unnecessary contents. After that the users can enter programs into this chip. The users can use this memory any number of times.
Secondary Storage or External Storage:
The primary memory of the computer stores the data as long as the power supply is on. If the power supply is off the contents from the main memory will be erased. The user can’t retrieve any information. So that the necessity of permanent or secondary storage. The secondary storage is a media or device which stores the data permanently. The user can read the information from the secondary storage devices when ever required. There are different types of seconds storage devices are available. The secondary storage is used to store the user’s data, system software, application software etc., The common secondary storage devices are:
Magneto Optical Storage.
1. Magnetic Storage : Magnetic Storage media is permanent storage media i.e., this memory is not volatile. These are permanent storage media. In magnetic storage the devices are made up of magnetic material. In magnetic storage, magnetic material coated with Iron Oxide. The different types of magnetic storage devices are:
1. Floppies 2. Hard Disk and 3. Magnetic Tapes
1. Floppy Disk: These are also called diskettes. These are used to transfer the data from one computer to another computer, which are not connected. The information in floppies is stored in the form of round concentric circles called Tracks and Sectors. The information in this device is not visible to the user. Only the system can read the information from this device using a drive system. These are removable diskettes. If the user wants to store or read the information from these devices, the disk must to be inserted into the system units drive system.
2. Hard Disk: This is a fixed disk inside the C.P.U having very large storage capacity. These disks are made up off Aluminum and coated with Iron Oxide. Hard disk comes along with the drive system and disk inside it. The user can use one are more hard disks in a system. The memory capacity of a hard disk is 20 MB to 80 GB. The hard disk inside the drive rotates at a speed of 3600 resolutions per minute. The data transfer rate of a hard disk is generally 4 MB per second i.e. it can send 4 MB data into main memory (RAM) at a time. Storing the information and accessing the information with hard disk is very fast compared with Floppy disk.
3. Magnetic Tapes: Magnetic tapes are used as secondary storage and also as back up memory. Back up the data of the hard disk needs so many floppies because of the lowest storage capacity. But a magnetic tape is enough to back up the entire contents of a hard disk, because of the highest storage capacity. Magnetic tape contains storage capacity of 1 GB to 20 GB i.e. similar to a hard disk. The main disadvantage of magnetic tap is the way of storing information. The information will be stored in magnetic tapes sequentially. The magnetic tape contains 9 tracks.
2. Optical Storage Devices: These are also secondary storage devices which are made with Polycarbonate. The disk is coated with a material which will be readable by focusing high intensity of laser beam. It contains much memory capacity i.e., a 5 1/4 inch optical disk contains 550 MB storage capacity. The information in these disks will be read only i.e., user can read the information from the disk and can’t write any information on to it. And some optical disk like erasable optical disk are assumptions from read only memory ( ROM ). The system seeks (accessible) the information very slowly comparing with HD. Some Optical disks are:
1. CD-ROM 2. WORM and 3. Erasable Optical Disk.
CD-ROM: (Compact Disk Read Only Memory): These are used for the storage of permanent programs that will be not modified in near future. The information in these disks will be written by the manufactures and the information will be useful to the user in case of reading only. The users can’t modify, delete, and rewrite the information onto these disks. CD-ROMs use tracks i.e., long spiral to store the information. The information stored in these disks be not changed or modified but the user can read the information whenever, she/he wants. This is nothing but, a type of Read Only Memory similar to PROM.
Input unit is used to give the data to the computer. Computer receives the data from the input unit. Input unit is the device, which is used to enter the data into the computer. There are different types of input devices available in the market. The basic input device for every computer is Keyboard. Some other input devices are Mouse, Trackball, Joystick, Scanner, Barcode Readers, etc.
1. Keyboard: Keyboard is the primary or standard input device to enter the data. There are different types of keyboards available in the market. IBM developed the standard keyboard layout. All the Models of the keyboards are identical to the IBM standard keyboard. The keyboards contain QWERTY type layout i.e. similar to Typewriter.
The keyboard contains different types of keys. There are 108 keys in the keyboard. The keys are.
Alpha Numeric keys
Arrow Keys (or) Cursor Control keys
2. Mouse: Mouse is the Pointing Device and was first introduced by Apple Macintosh computers in 1984. Mouse is also one of the common input devices and it was used to work with computer with the help of mouse by selecting the objects and commands.
Mouse is a pint and Click device. On the monitor there will be an arrow key to represent the mouse pointer. The user can move the mouse pointer to select objects and commands by moving the mouse on flat surface. Moving the mouse on flat surface effect the mouse pointer on the screen.
In general, Mouse contains 2 Buttons called Left and Right Button.
Pressing the Mouse button twice is called Double clicking.
Dragging is also Mouse technique used to move an Object from one location to another location on the screen. Dragging is selecting the object, moving the object to the designation while holding the mouse button.
3. Light Pen: Some computers use light pens as input device. Light pen is a pen like device connected to the computer and it uses a pad to write with the pen. Users use a light pen by writing on the pad. It this, the pad translates the user given information to computers. In some cases the users points the pen on the screen and selects the command. This is also called as Hand-Writing Recognition Technology.
4. Touch Screen: A Touch screen allows the user to pint directly on the screen with the fingers. In touch screens the screen display a group of objects and selects information by pointing the finger on the screen. The screen receives the sensors signed and executes the commands. These are used in public places like railway stations, Airports, etc.
5. Bar Code Readers: A Bar code Reader is also popular input device, which is used to departmental stores and in super markets. A Barcode is a special code to represent numbers in the form of lines. In some cases the users have to enter the Bar codes as data to the computer. By putting the barcode reader on the code the devices reads the lines and converts the information to numbers and sends to the computer.
6. Scanner: scanners are also one of the types of input device used to input much amount of information at a time. In some cases the user has to input images into the computer. The Scanner is the device and the user have to put the existing information of paper into the scanner and the scanner reads the information to computer. Scanner converts the information or image, which was put on to the scanner into electronic format. The different types of scanners are Flat Scanners, Hand Held Scanners, etc.
Output unit is used to present the processed result to the user. The basic Output device is Monitor or VDU (Visual Display Unit). Some other output devices are Printers, Plotters, Sound Systems and Speakers, etc.
The most common output devices are Monitors. In general there are 2 types of Monitors.
CRT(Cathode Ray Tube) Monitor
Flat-Panel Model Monitor
This is seen on desktop computers which look like a TV screen and works the same way this monitor uses a large Vacuum tube called Cathode Ray Tube. These CRT screens are capable of displaying much higher resolutions. To display colors on a CRT screen each pixel on the screen is divided into 3 parts Red, Green and Blue.
Flat Panel Model:
These are generally used with notebook computers. CRT monitors are big and require lot of power hence are not generally used with notebook computers. The flat panel display creates an image using LCD (Liquid Crystal Display) technology. The LCD monitor creates images with a special form of Liquid Crystal that is transparent but become opaque when charged with electricity.
These printers are very fast and their print quality is higher. They can print either or more pages per minute. Laser printer output can be both text and graphics and can be very close to Professional printing quality. Laser makes up on an entire page before printing it. The quality environments where several users can share the same printer easily via LAN.
This is another type of laser printers, which prints both sides of sheet of paper at the same time.
These are used mainly for printing large line art such as engineering or architectural drawings. Plotters output can be up to several yards long. Pen plotters are the most common types. There are also other kinds of plotters inkjet plotters are cheaper but they consumes ink rapidly and the ink is smear able until dry.
4. Sound Systems:
When you buy a multimedia PC, you will get a machine that includes CD-ROM drive, a High quality video Controller, speakers and Sound cards.
The speakers attached to systems are similar as connect Stereo. The only difference is that they are usually smaller and they contain their own small amplifiers.
The important part of the sound output system is in the sound card. The Sound card translates Digital sound signals into electronic current that is sent to the speakers.
by : Satya